Brake Light Conundrum

Hello everyone,
As I am writing this I am angrily sitting inside of a partially disassembled 2001 GT Convertible. As I was getting an inspection done the other day, the inspector pointed out that my third brake light was not working. Seeing how my poor old high mileage GT has spent most of the summer in a leaky dank garage and had developed a layer of nasty even in the interior, I figured corroded plug. But then the brake lights went away, and the blinkers, they didnt even come on when I pulled the headlight switch . So I got to work. Replaced every conceivable fuse, multifunction switch, blinker module and brake switch (which is testing good). Now I have blinkers and they come on with the head lights but still no brakes or third brake light. I know its probably a wire, or ground, or crappy connection somewhere but after tearing this thing apart and becoming frustrated I have come here to hopefully find someone who has had this same problem and can point me in a specific direction. BTW for context, on the day I went and had two new tires installed on the front, had my big 315s in the rear balanced and then drove about 6 miles and as far as I know my lights were functioning (at least blinkers were) and seemed to all have a meltdown during the inspection.

Let me try to be a little more clear now that I've walked away and stopped thinking about smashing it with a hammer.

First, everything went out in the rear. No blinkers, to brake lights, no third brake, and they didn't light up when the headlights were on.

So, I started replacing the usual suspects just to cover my bases. The multifunction switch, the blinker module, the brake sensor, and multiple fuses that had anything to do with lights.

So now the current state is that the blinkers blink, and the tail lights come on when the headlights are on like normal.

They still dont light up when the brakes are pushed and the third light is still dead.

Which makes me think its a wiring issue somewhere between the brake sensor and the lights seeing how they still illuminate and blink under other circumstances.

Also, I dont know how many owners this thing has had before me but the deeper I get into the wiring the more random crap and splices im finding which is probably also part of the problem.

weendoggy said:

OK, I'm going to attempt a check, if the switch is working fine, use a test light or DVOM to see if you have current to the rear harness at the lights. If not, find out why. If you do, but when plugged in they don't work, you have a bad or non existing ground issue, most likely in that vicinity.

Why are blinkers coming on with the head lights on? They don't work through that switch and should work regardless if the head lights are on or not, confusing? Are you sure you don't mean tail lights?

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Also I didn't mean they come on with the headlights. Bad wording. I just meant the tail lights come on with the headlights where they were dead before.

weendoggy said:

OK, I'm going to attempt a check, if the switch is working fine, use a test light or DVOM to see if you have current to the rear harness at the lights. If not, find out why. If you do, but when plugged in they don't work, you have a bad or non existing ground issue, most likely in that vicinity.

Why are blinkers coming on with the head lights on? They don't work through that switch and should work regardless if the head lights are on or not, confusing? Are you sure you don't mean tail lights?

Click to expand...

I fixed it. Turned out to be a super corroded connector in the driver side kick panel. Cleaned it up with some QD electronic cleaner and reconnected some broken contacts with blade connectors and bob's your uncle.

Aunt Fannie is the one you have to watch out for.